This project aims to determine if certain biological factors, namely low platelet MAO, abnormalities on the CAT Scan, or left-handedness have an etiological relationship with schizophrenia. The method involves finding schizophrenics with one of these factors and studying the relatives to see if the factor and schizophrenia segregate together in these pedigrees. The work on this project to date has involved only sample collection (i.e., interviewing schizophrenics) and the development of an interview schedule for borderline schizophrenia. No analyses have yet been done.